1. Technical Field
The present invention relates to mobile shopping bags; in particular the invention relates to shopping bags that, distinct from bag carriers, are themselves mobile for wheeled portage of consumer purchases.
2. Description of Related Art
Consumers in shopping centers and supermarkets often find themselves with bulky. purchases such as food and cleaning items that they need to transport some considerable distance by hand, and yet are without a personal handcart. This is most likely because they either do not own or wish to own a handcart, which is rather unwieldy, or do not wish to or have forgotten to bring one along.
To address the problem of a ready means for towing shopping bags heavy with purchases, a disposable shopper's cart, for example, has long since been proposed. U.S. Pat. No. 2,868,557 to Klipp and Abramson discloses such a cart. The disposable shopper's cart is formed of a single sheet of a stiff material such as cardboard, and is assembled by first folding up longitudinal rear and flanking lateral walls, which interlock by tabs. Wheels are then secured to the cart body, either on a single axle passing along the rear inside corner, or on a pair of stub axles each locked into the respective rear corners.
Clearly, the assembled disposable shopper's cart as described in the Klipp and Abramson patent has drawbacks in how the assembled cart bears weight on the wheels. Wherein a long axle carries the wheels, the axle is liable to bend, impeding the mobility of the cart; the stub axles would bear weight better, but are liable to rotate out of true, destabilizing the cart's mobility.
Moreover, the cart as taught by Klipp and Abramson requires fastening retaining cords to the cart body in order to hold a shopping bag in the cart.
U.S. Pat. No. 3,197,225 to Powell recognizes the foregoing problems and contemplates a hand-portable, collapsible shopping cart with rigid base plates and unilateral wall plates for withstanding heavy loads. A shopping cart embodied according to the Powell disclosure is fashioned from durable materials including a fabric bag and plates of aluminum, and is clearly not designed to be disposable. Furthermore, the shopping cart as claimed and taught by Powell in the principal embodiment trundles on unilateral rolling means (ball casters) mounted on a beveled surface of the bottom plate to keep the casters out of the way when the bag is opened and set down for loading. The ball casters are fixed to the beveled surface "by riveting, bolting, welding, pin-clenching or the like." The configuration essentially has the wheels mounted at the vertex where the bottom and side plates of the cart join.
Collapsible shopping carts described by Powell thus are neither mass-producible nor disposable, and the cart must be tilted onto the rolling means before the cart is mobile.
A collapsible, wheeled base assembly to which a large bag may be attached is disclosed in U.S. Pat. No. 4,596,397 to Conti. To assemble the device for use as a mobile shopping bag, a large sack such as a garbage bag is folded into a pleat around the bottom of the opened bag for insertion into pin-and-cap fittings at the corners of the base assembly. This operation would seem awkward to accomplish, although the disclosure does mention that the bag may be cemented to the base.
As taught in the Conti patent, the pair of wheels is mounted to the base on horizontally extending axles. The base is designed with a wing conformation to strengthen its rigidity, and presumably the bag-and-base assembly trundles more stably than the cart described in the Klipp and Abramson patent. Nevertheless, not only does the mobile shopping bag assembly described by Conti seem bothersome to assemble, but it also seems that in use the pleats in the bag clenched by or cemented onto the base assembly would undergo strain that could rend the bag.
Accordingly, a mobile yet disposable shopping bag that can be readily assembled by the user or pre-assembled by the merchant is desirable. Disposability is desirable since even if consumers own portable shopping carts they often tend not to bring them on shopping trips. Shoppers tend not to anticipate every instance in which their purchases become such that they wish to have mobile bag if one is at hand.